Desulfurization of delayed petroleum coke

Abstract

Delayed coke is desulfurized by first contacting the coke with an active sulfur-bearing gas at a temperature high enough to produce a reaction between the sulfur in the coke and the active sulfur in the gas, and then holding the coke in contact with the gas at said high temperature for approximately one hour. An alternative process provides for desulfurization of delayed coke by modifying the second step of the prior process to dilute or replace the sulfur-bearing gas with an inert gas. In a third alternative, the foregoing process is further modified by lowering the temperature during the second or holding step to maintain the reaction between the sulfur-bearing gas and the coke.

What is claimed is: 
     
       1. A process for desulfurizing delayed coke of high sulfur content above 3% by weight, which comprises the steps of (a) raising said coke to an elevated reaction temperature in the range of 1400° to 1600° C.,   (b) contacting said elevated temperature coke with a first added active sulfur-bearing gas for a first period of about 5 minutes to 30 minutes wherein said first added gas is selected from the group consisting of hydrogen sulfide, carbonyl sulfide, refinery sour gas, mercaptans, carbon disulfide, a mixture of carbonyl sulfide with water, and a mixture of carbon monoxide and sulfur dioxide, wherein said first added gas is purged at the end of said first period, and   (c) then contacting said coke from step (b) with a second added gas for a second period of up to one hour and maintaining said elevated temperature to obtain coke of reduced sulfur content, wherein said second added gas is selected from the group consisting of (i) an inert gas and (ii) said first added gas diluted with an inert gas.   
     
     
       2. A process for desulfurizing delayed coke which comprises the steps of (a) raising said coke to a first reaction temperature in the range of 1400° C. to 1600° C.,   (b) supplying to said coke at said first reaction temperature for a first period of about 5 minutes to 30 minutes a first added active sulfur-bearing gas selected from the group consisting of hydrogen sulfide, refinery sour gas, mercaptans, carbon disulfide, carbonyl sulfide, a mixture of carbonyl sulfide with water, and a mixture of carbon monoxide and sulfur dioxide, wherein said first added gas is purged at the end of said first period, and   (c) then contacting said coke from step (b) with a second added gas for a second contact period of up to one hour at a second reaction temperature lower than said first reaction temperature to obtain coke of reduced sulfur content, wherein said second added gas is selected from the group consisting of (i) an inert gas and (ii) said first added gas diluted with an inert gas.   
     
     
       3. A process according to claim 2 in which said coke is again exposed to said second added gas after said second contact period for a third contact period at the same reaction temperature as said second reaction temperature.